The present invention relates to warheads and, in particular, it concerns a wall breaching warhead for making a hole of diameter sufficient to allow passage of personnel through a wall.
During military operation in urban terrain (MOUT), the ability to break quickly into buildings with minimum risk to the operating force is an obvious advantage.
Breaching of walls, particularly walls made from bricks, slabs or blocks (referred to generically herein as xe2x80x9cbrick wallsxe2x80x9d) presents significant difficulties. Specifically, the shock waves of a blast tend to be transmitted through the front layer(s) of a brick wall, causing disintegration of the rearmost layer without causing significant damage to the front layer. As a result, a conventional blast warhead is typically only effective if a very large warhead is used, in the order of 10-20 kg of explosive, located against the wall. Such a large charge constitutes a hazard to the operating force and may cause excessive unwanted damage to personnel and property in the vicinity.
Other known techniques include attachment of a frame of a linear shaped charge to the wall to cut it, or use of an explosive annular shaped charge mounted in a pre-drilled hole to produce a larger hole. Both of these options requires manual extensive preparation adjacent to the wall, which is slow and, in many cases, exposes the operating force to unacceptable risk.
A further possibility is the use of a flexible squashed charge, which is shot dynamically towards the wall. Squashing of the explosive increases the contact area between the explosive and the wall, thereby enhancing the efficiency of delivering explosive energy to the wall. However, since it is detonated on the wall, only a relatively small hole is created.
None of the above techniques provides a warhead which is light enough to be shot dynamically from a remote position, which is effective to produce a man size hole in a brick wall, and which does not cause excessive damage to surrounding personnel and property.
There is therefore a need for a lightweight warhead which would be effective to breach brick walls.
The present invention is a wall breaching warhead for forming a hole through a brick wall.
According to the teachings of the present invention there is provided, a wall breaching warhead for forming a hole through a brick wall, the warhead comprising: (a) a shaped charge of explosive material having a central axis, the charge having a front surface including: (i) a central portion adjacent to the central axis having a generally convexly-curved shape, and (ii) an annular portion circumscribing the central portion, the annular portion having a generally concavely-curved shape; and (b) a metallic liner adjacent to at least the annular portion of the front surface.
According to a further feature of the present invention, the concavely-curved shape exhibits a concave profile as viewed in a cross-section through the shaped charge passing through the central axis, at least a major part of the concave profile being configured such that a vector projecting outward from, and perpendicular to, the front surface diverges from the axis.
According to a further feature of the present invention, the shaped charge has a length measured parallel to the central axis and an outer diameter measured perpendicular thereto, the outer diameter being about twice the length.
According to a further feature of the present invention, the shaped charge includes between about xc2xd kg and about 3 kg of explosive material Most preferably, the shaped charge includes less than about 2 kg of explosive material.
According to a further feature of the present invention, the metallic liner covers substantially the entirety of the front surface.
According to a further feature of the present invention, there is also provided a stand off detonation system including means for defining a stand off detonation distance of the shaped charge from the wall. Preferably, the means for defining a stand off detonation distance includes a stand off rod projecting from the front surface substantially parallel to the central axis.
According to a further feature of the present invention, the shaped charge has a rear surface, the warhead further comprising a rear cover associated with at least the rear surface, the rear cover being formed from non-penetrating material.
According to a further feature of the present invention, the annular portion corresponds to at least about half of the total area of the front surface as viewed parallel to the central axis.